With the advance of techniques for manufacturing thin-film transistors, the liquid crystal displays (LCD) are widely applied in electrical products, such as PDAs, laptops, digital cameras, cell phones, high resolution television sets, etc. due to advantages as portability, non-radiation and saving electricity. Especially when the manufactures devote themselves to further research and improve the materials, processes and equipments for producing LCD devices, the qualities of the LCDs are promoted and prime costs are reduced substantially:
In general, on these electronic products, such as PDAs or notebook, are assembled with keyboards for providing consumers to input data and orders. However, because the current design trend of the electronic products is towards portability, the keyboards occupied the part space of the electronic products usually hinder from the portability. For solving this problem, touch screens are introduced to the electronic products.
In the conventional touch screen, a touch panel is fabricated on a display to provide consumers convenience to input data and orders by utilizing a hand-held stylus in conjunction with the touch screen display. However, because it is indispensable to fabricate the touch panel onto the surface of display, some light source is obstructed, and thus the image displaying efficiency is decreased. Even though the transparency of the touch panel in current products is promoted about 85%, for most electronic products with touch panels, the extra backlight sources are still required to provide enough illumination. And the transparency limitation of the touch panel still squanders lots of electrical power.
For thoroughly overcoming the above issues, the display manufacturers apply the digitizer to substitute for the conventional touch screen. Please refer to FIG. 1, a liquid crystal display 10 integrated with a digitizer 40 is illustrated. In general, the liquid crystal display 10 comprises a glass panel 20 and a backlight module 30. The glass panel 20 has an upper glass substrate 22, a lower glass substrate 24, and a liquid crystal layer inserted therebetween. On the lower glass substrate 24 some pixel arrays composed of thin film transistors are fabricated. A printed circuit board assembly (PCB assembly) 27 is electrically connected to the lower glass substrate 24 via a flexible printed circuit (FPC) 29. By using a timing control chip 25 fabricated on the PCB assembly 27, the pixel arrays can be switch on or off to form pictures on the display.
The backlight module 30 comprises a lightguide 32, optical films 34, a white sheet 36, a lamp 38 and a reflector cover 39. The lightguide 32 made of acrylics is applied to provide light propagating paths. Aside the lightguide 32 mounted the lamp 38 is applied to illuminate the lightguide 32 in the edgelight form. The light entering from one side of the lightguide 32 can propagate to another side thereof in the total reflection form. Aside the lamp 38 the reflector cover 39 is applied to prevent the lights from dissipating. The white sheet 36 is disposed beneath the lightguide 32 to reduce light dispersing. And the optical films 34 having some diffuser films and brightness enhancing films are introduced to scatter the light more uniformly.
Besides, the digitizer 40 comprises a sensor board 42 and a control board 44. The sensor board 42 has grid type of antenna arrays formed therein to receive electromagnetic signals. When consumers utilize a hand-held stylus to select or input data on the glass panel 20, the sensor board 42 can receive the electromagnetic signals and transfer these signals to the control board 44 via a connecting bus 46. Then the control board 44 can decode these signals and communicate with the motherboard of the electronic product. On the control board 44 an ASIC chip 48 is mounted for providing the above decoding and communicating functions.
In the conventional assembling procedures for the backlight module 30, a bezel and a frame are jointed together for receiving the components of lightguide 32, optical films 34, the white sheet 36, the lamp 38 and the reflector cover 39. Next the backlight module 30 and the glass panel 20 are disposed and received in a display frame. And the display manufacture will use screws to fix the backlight module 30 and the glass panel 20 onto the display frame. After assembling the liquid crystal display module 10, the display manufacturer will use screws again to fasten the sensor board 42 and the liquid crystal display module 10, and then exports these products to system manufacturers. After that, the system manufacturers can integrate the liquid crystal display module 10 and the digitizer 40 into different electronic apparatus, such as laptops, PDAs, etc.
Notedly, when the system manufacturer assembles the liquid crystal display module 10 into the electronic apparatus, they still have to utilize screws to fasten the sensor board 42 into the electronic apparatus. Therefore, it is indispensable to form additional fastening holes on the sensor board 42, first for providing the display manufacturer to fasten the sensor board 42 onto the liquid crystal display module 10, and next for providing the system manufacturer to fasten the sensor board 42 into the electronic apparatus.
This assembling manner apparently has some disadvantages. First, the number of fastening times is too much, and thus the producing cycle time is too long. Second, on the sensor board it is required to form extra fastening holes and utilize more screws for fastening the sensor board and the liquid crystal display module firstly, and for fastening the sensor board into the electronic apparatus sequently, so the production cost is excess. Besides, the available space of the liquid crystal display module 10 is also limited by the extra fastening holes and screws.